Method and apparatus for creating formed elements used to make wound stents

ABSTRACT

A method for forming a wave form for a stent includes moving a first forming portion of a first forming member across an axis along which a formable material is provided in a first direction substantially perpendicular to the axis to engage and deform the formable material while engaging the formable material with a first forming portion of the second forming member. The method includes moving the first forming portion of the first forming member and the first forming portion of the second forming member across the axis in a second direction that is substantially opposite the first direction to draw and form the formable material over the first forming portion of the second forming member, disengaging the first forming member from the formable material, and rotating the first forming member to position a second forming portion of the first forming member to face the formable material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally related to an apparatus and methodfor forming a wave form for a stent. More particularly, the presentinvention is related to an apparatus and method for forming the waveform from a formable material, such as a wire or a strip of material.

2. Background of the Invention

A stent is typically a hollow, generally cylindrical device that isdeployed in a body lumen from a radially contracted configuration into aradially expanded configuration, which allows it to contact and supporta vessel wall. A plastically deformable stent can be implanted during anangioplasty procedure by using a balloon catheter bearing a compressedor “crimped” stent, which has been loaded onto the balloon. The stentradially expands as the balloon is inflated, forcing the stent intocontact with the body lumen, thereby forming a support for the vesselwall. Deployment is effected after the stent has been introducedpercutaneously, transported transluminally, and positioned at a desiredlocation by means of the balloon catheter.

Stents may be formed from wire(s) or strip(s) of material, may be cutfrom a tube, or may be cut from a sheet of material and then rolled intoa tube-like structure. While some stents may include a plurality ofconnected rings that are substantially parallel to each other and areoriented substantially perpendicular to a longitudinal axis of thestent, others may include a helical coil that is wrapped or wound arounda mandrel aligned with the longitudinal axis at a non-perpendicularangle.

Stent designs that are comprised of wound materials generally havecomplex geometries so that the final stents may be precisely formed. Thesmall size and complexity of some stent designs generally makes itsformation difficult. Wound stents are formed such that when unsupported,they create the desired stent pattern and vessel support. This processgenerally involves winding a source material around a supportingstructure such as a rod or mandrel and creating a helical or spring-likewrap pattern. To provide greater support, along this wrapped element,geometries are formed into the source material to better support thetissue in between each wrap, usually of sinusoidal nature. A potentialdown side to a wrapped stent is that the ends of the stent are generallynot perpendicular to the longitudinal axis of the stent, but ratherterminate at a pitch angle induced by the helical wrapping.

SUMMARY OF THE INVENTION

Embodiments of the present invention describe an apparatus and methodfor forming a wave form for a stent that provides formed geometries thatcan alter a pitch angle such that the wound stent terminates at asubstantially perpendicular angle to the longitudinal axis of the stent.More specifically, the apparatus and method according to embodiments ofthe present invention allow for the amplitude and wavelength of anyindividual or half element of the wave form to be manipulated to providethe desired interwrap support.

According to an aspect of the present invention, there is provided amethod for forming a wave form for a stent. The method includesproviding a length of a formable material from a supply of the formablematerial in a feeder along an axis in a first direction in between afirst forming member and a second forming member. The second formingmember is positioned closer to the feeder than the first forming member.The method also includes moving a first forming portion of the firstforming member across the axis in a second direction substantiallyperpendicular to the first direction to engage and deform the formablematerial while engaging the formable material with a first formingportion of the second forming member, moving the first forming portionof the first forming member and the first forming portion of the secondforming member across the axis in a third direction that issubstantially opposite the second direction to draw and form theformable material over the first forming portion of the second formingmember, disengaging the first forming member from the formable material,and rotating the first forming member. The method further includesmoving the first forming member and the second forming member relativeto each other so that the first forming member is positioned closer tothe feeder than the second forming member, moving a second formingportion of the first forming member into engagement with the formablematerial, and moving the second forming portion of the first formingmember and the first forming portion of the second forming member acrossthe axis in the second direction to draw and form the formable materialover the second forming portion of the first forming member.

According to an aspect of the present invention, there is provided aforming apparatus configured to form a wave form for a stent out of aformable material. The wave form includes a plurality of substantiallystraight portions and a plurality of curved portions. The apparatusincludes a feeder constructed and arranged to receive a supply of theformable material and to provide the formable material along an axis,and a first forming member configured to be movable along two orthogonalaxes and rotatable in a plane defined by the two orthogonal axes. Thefirst forming member includes a first forming portion and a secondforming portion having a shape different from the first forming portion.Each of the first forming portion and the second forming portion isconfigured to engage and deform the formable material. The apparatusalso includes a second forming member positioned on an opposite side ofthe axis relative to the first forming member. The second forming memberis configured to be movable along the two orthogonal axes and comprisinga first forming portion configured to engage and deform the formablematerial. The apparatus also includes a controller in communication withthe feeder, the first forming member, and the second forming member. Thecontroller is configured to control movement of the first and secondforming members to form the wave form.

According to an aspect of the present invention, there is provided amethod for forming a wave form for a stent. The method includesproviding a length of a formable material from a supply of the formablematerial in a feeder along an axis in a first direction in between afirst forming member and a second forming member, the second formingmember being positioned closer to the feeder than the first formingmember. The method includes moving a first forming portion of the firstforming member into contact with the formable material and across theaxis in a second direction substantially perpendicular to the firstdirection, and folding the formable material over a first formingportion of the second forming member by moving the second forming memberand the first forming member in a third direction substantially oppositethe second direction and moving the second forming member and the firstforming member in a fourth direction substantially opposite the firstdirection. The method includes disengaging the first forming member fromthe formable material, rotating the first forming member, and moving asecond forming portion of the first forming member into engagement withthe formable material at a position closer to the feeder than the secondforming member. The method includes drawing a length of the formablemember from the feeder with the first forming member and the secondforming member, and folding the formable material over the secondforming portion of the first member by moving the first forming memberand the second forming member in the second direction and moving thefirst forming member and the second forming member in the fourthdirection.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying schematic drawings in whichcorresponding reference symbols indicate corresponding parts, and inwhich:

FIG. 1 is a schematic view of an embodiment of a forming apparatusconfigured to deform a formable material into a desired wave form for astent, with the formable material being provided in a first direction bya feeder;

FIG. 2 is a schematic view of the forming apparatus of FIG. 1, with afirst forming member being moved in a second direction substantiallyperpendicular to the first direction to deform the formable materialinto a half element of the wave form;

FIG. 3 is a schematic view of the forming apparatus of FIG. 2, with asecond forming member and the first forming member being moved in athird direction substantially opposite the second direction to deformthe formable material into another half element of the wave form;

FIG. 4 is a schematic view of the forming apparatus of FIG. 3, with thefirst forming member moving away from the formable material and towardsthe feeder;

FIGS. 5A-C are schematic views of the first forming member being rotated90°;

FIG. 6 is a schematic view of the forming apparatus of FIG. 4, with thefirst forming member, after being rotated 90°, being moved towards theformable material in the second direction;

FIG. 7 is a schematic view of the forming apparatus of FIG. 6, with thefirst forming member and the second forming member being moved in thesecond direction to deform the formable material into another halfelement of the wave form;

FIG. 8 is a schematic view of the forming apparatus of FIG. 7, with thesecond forming member moving away from the formable material and towardsthe feeder;

FIGS. 9A-9C are schematic views of the second forming member beingrotated 90°;

FIG. 10 is a schematic view of the forming apparatus of FIG. 8, with thesecond forming member, after being rotated 90°, being moved towards theformable material in the third direction;

FIG. 11 is a schematic view of the forming apparatus of FIG. 10, withthe first forming member and the second forming member being moved inthe third direction to deform the formable material into another halfelement of the wave form;

FIG. 12 is a schematic view of the forming apparatus of FIG. 11, withthe first forming member moving away from the formable material andtowards the feeder;

FIGS. 13A-C are schematic views of the first forming member beingrotated 90°;

FIG. 14 is a schematic view of the forming apparatus of FIG. 12, withthe first forming member, after being rotated 90°, being moved towardsthe formable material in the second direction;

FIG. 15 is a schematic view of the forming apparatus of FIG. 14, withthe first forming member and the second forming member being moved inthe second direction to deform the formable material into another halfelement of the wave form;

FIG. 16 is a schematic view of the forming apparatus of FIG. 15, withthe second forming member moving away from the formable material andtowards the feeder;

FIGS. 17A-17C are schematic views of the second forming member beingrotated 90°;

FIG. 18 is a schematic view of the forming apparatus of FIG. 16, withthe second forming member, after being rotated 90°, being moved towardsthe formable material in the third direction;

FIG. 19 is a schematic view of the forming apparatus of FIG. 18, withthe first forming member and the second forming member being moved inthe third direction to deform the formable material into another halfelement of the wave form;

FIG. 20 is a schematic view of the forming apparatus of FIG. 19, withthe first forming member moving away from the formable material andtowards the feeder; and

FIGS. 21A-C are schematic views of the first forming member beingrotated 90°;

FIG. 22 is a schematic view of the forming apparatus of FIG. 20, withthe first forming member, after being rotated 90°, being moved towardsthe formable material in the second direction;

FIG. 23 is a schematic view of the forming apparatus of FIG. 22, withthe first forming member and the second forming member being moved inthe second direction to deform the formable material into another halfelement of the wave form;

FIG. 24 is a schematic view of the forming apparatus of FIG. 23, withthe second forming member moving away from the formable material andtowards the feeder;

FIGS. 25A-C are schematic views of the second forming member beingrotated 90°;

FIG. 26 is a schematic view of the forming apparatus of FIG. 24, withthe second forming member, after being rotated 90°, being moved towardsthe formable material in the third direction;

FIG. 27 is a schematic view of the forming apparatus of FIG. 26, withthe first forming member and the second forming member being moved inthe third direction to deform the formable material into another halfelement of the wave form;

FIG. 28 is a schematic view of an embodiment of the forming apparatus ofFIG. 1, with the formable material being provided in the firstdirection;

FIG. 29 is a schematic view of the forming apparatus of FIG. 28, withthe first forming member being moved in the second direction to deformthe formable material;

FIG. 30 is a schematic view of the forming apparatus of FIG. 29, withthe formable material being drawn from the feeder in the first directionby movement of the first forming member and the second forming member;

FIG. 31 is a schematic view of the forming apparatus of FIG. 30, withthe first forming member and the second forming member being moved inthe third direction;

FIG. 32 is a schematic view of the forming apparatus of FIG. 31, withthe first forming member and the second forming member being moved in afourth direction, which is opposite the first direction;

FIG. 33 is a schematic view of the forming apparatus of FIG. 32, afterthe first forming member has been moved to a position in between thefeeder and the second forming member;

FIG. 34 is a schematic view of the forming apparatus of FIG. 33, withthe formable material being drawn in the first direction by movement ofthe first forming member and the second forming member;

FIG. 35 is a schematic view of the forming apparatus of FIG. 34, withthe first forming member and the second forming member being moved inthe second direction;

FIG. 36 is a schematic view of the forming apparatus of FIG. 35, withthe first forming member and the second forming member being moved inthe fourth direction;

FIG. 37 illustrates an embodiment of a wave form generated by theforming apparatus of FIGS. 1-36; and

FIG. 38 illustrates an embodiment of a wave form generated by theforming apparatus of FIGS. 1-36.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and use of theinvention. Furthermore, there is no intention to be bound by anyexpressed or implied theory presented in the preceding technical field,background, brief summary or the following detailed description.

FIG. 1 schematically illustrates an embodiment of a forming apparatus 10that is configured to deform a formable material 12 into a desiredshape, i.e. wave form, as discussed in further detail below. The formingapparatus 10 includes a feeder 14 that is constructed and arranged toreceive a supply of the formable material and to provide the formablematerial 12 substantially along an axis AX in a first direction FD. Thefeeder 14 may be configured to actively feed the formable material 12along the axis AX in the first direction, or may be configured topassively feed the formable material by allowing the formable material12 to be drawn from the feeder 14, as discussed in further detail below.The forming apparatus 10 also includes a controller 16 that isconfigured to communicate with the feeder 14. The controller 16 may beprogrammed to provide signals to the feeder 14 so that the feeder 14feeds the formable material 12 at a desired rate or velocity, and alsostops feeding the formable material 12 when desired.

The forming apparatus 10 also includes a first forming member 20 and asecond forming member 30. The first forming member 20 includes a firstforming portion 22 that has a first engaging surface 23 at a distal endthereof, a second forming portion 24 that has a second engaging surface25 at a distal end thereof, a third forming portion 26 that has a thirdengaging surface 27 at a distal end thereof, and a fourth formingportion 28 that has a fourth engaging surface 29 at a distal endthereof. The engaging surfaces 23, 25, 27, 29 are configured to engagethe formable material 12 on one side thereof and deform the formablematerial 12 into a desired shape, as discussed in further detail below.Each of the forming portions 22, 24, 26, 28 may generally be elongatedor finger-like in shape, as illustrated, but the illustrated embodimentsshould not be considered to be limiting in any way.

Similar to the first forming member 20, the second forming member 30includes a first forming portion 32 that has a first engaging surface 33at a distal end thereof, a second forming portion 34 that has a secondengaging surface 35 at a distal end thereof, a third forming portion 36that has a third engaging surface 37 at a distal end thereof, and afourth forming portion 38 that has a fourth engaging surface 39 at adistal end thereof. The engaging surfaces 33, 35, 37, 39 are configuredto engage the formable material 12 on one side thereof and deform theformable material 12 into a desired shape, as discussed in furtherdetail below. Each of the forming portions 32, 34, 36, 38 may generallybe elongated or finger-like in shape, as illustrated, but theillustrated embodiments should not be considered to be limiting in anyway.

As illustrated in FIG. 1, the first forming member 20 and the secondforming member 30 are positioned so that the first engaging surface 23of the first forming member 20 and the first engaging surface 33 of thesecond forming member 30 face each other on opposite sides of theformable material 12.

The first forming member 20 and the second forming member 30 may bemoved relative to the feeder 14 by actuators 40, 50, respectively, thatare schematically illustrated in FIG. 1. Each of the actuators 40, 50 isin communication with the controller 16 so that the controller 16 maysend signals to the actuators 40, 50 to control movement of the firstand second forming members 20, 30, respectively. A suitable motor oractuator 42 that is in communication with the controller 16 may be usedto rotate the first forming member 20, and a suitable motor or actuator52 that is in communication with the controller 16 may be used to rotatethe second forming member 30. In addition, the feeder 14 may beconnected to an actuator (not shown) that is in communication with thecontroller 16 so that the controller may control movement of the feeder14 relative to the first and second forming members 20, 30.

In operation, the first forming member 20 is initially positioned on oneside of the axis AX, and the second forming member 30 is initiallypositioned on the opposite side of the axis AX relative to the firstforming member 20 such that the first engaging surface 23 of the firstforming member 20 and the first engaging surface 33 of the secondforming member 30 face each other, as illustrated in FIG. 1. In anembodiment, the controller 16 sends a signal to the feeder 14 to advancethe formable material 12 by a predetermined amount or length in thefirst direction FD substantially along the axis AX. In an embodiment,the feeder 14 does not actively advance the formable material 12, butinstead allows the formable material 12 to be drawn by the first formingmember 20 and/or the second forming member 30, as understood by one ofordinary skill in the art.

As illustrated in FIG. 2, the first forming member 20 is moved in asecond direction SD that is substantially perpendicular to the firstdirection FD and the axis AX so that the first engaging surface 23engages the formable material 12 and deforms the formable material 12 asthe first engaging surface 23 passes over the axis AX. The secondforming member 30 may hold its position relative to the axis AX untilthe first forming member 20 has completed its movement in the firstdirection FD.

FIG. 3 illustrates the second forming member 30 engaging the formablematerial 12 with the first engaging surface 33 and moving in a thirddirection TD that is substantially opposite the second direction SD andsubstantially perpendicular to the axis AX. At the same time or at aboutthe same time, the first forming member 20 also moves with the secondforming member 30 in the third direction TD while still engaging theformable material 12, and the feeder 14 feeds an additional amount offormable material 12 in the first direction FD or the feeder 14 allowsthe additional amount of formable material 12 to be drawn in the firstdirection FD. Due to the movement of the first and second formingmembers 20, 30, the formable material 12 folds over the top of the firstelongated portion 32 of the second forming member 30, as illustrated inFIG. 3, to form a half element (i.e., half wavelength) of the wave form.

As illustrated in FIG. 4, the first forming member 20 then disengagesfrom the formable material 12 and moves away from the formable material12 in the third direction TD. In addition, the first forming member 20moves towards the feeder 14 in a direction that is substantiallyopposite the first direction FD. At the same time, or about the sametime, the second forming member 30 moves in the first direction FD asthe feeder 14 provides a small amount of formable material 12 in thefirst direction FD, desirably at about the same rate that the secondforming member 30 moves in the first direction FD, to make room for thefirst forming member 20 in between the feeder 14 and the second formingmember 30. The formable material 12 may be drawn from the feeder 14 orthe feeder 14 may actively feed the formable material 12.

FIGS. 5A-C illustrate the rotation of the first forming member 20 about90° from its orientation illustrated in FIGS. 1-4. In the illustratedembodiment, the first forming member 20 is rotated in a counterclockwisedirection. In an embodiment, the first forming member 20 may be rotatedin a clockwise direction. Also, in an embodiment, the first formingmember 20 may be rotated about 180°. The illustrated embodiment is notintended to be limiting in any way.

The first forming member 20 then moves in the second direction SDtowards the formable material 12, engages the formable material 12 withthe second engaging surface 25, as illustrated in FIG. 6, and continuesto move in the second direction SD, as illustrated in FIG. 7. At thesame time, or about the same time, that the second engaging surface 25of the first forming member 20 moves across the axis AX and to theposition illustrated in FIG. 7, an additional length of the formablematerial 12 is provided to accommodate for the distance traveled by thesecond engaging surface 25 relative to the axis AX, and the secondforming member 30 moves at substantially the same speed as the firstforming member 20, in the second direction SD. The additional length maybe drawn from the feeder 14 or may be fed by the feeder 14, as discussedabove.

Similar to the movement of the first forming member 20 that isrepresented in FIG. 4, the second forming member 30 then moves away fromthe formable material 12 and away from the axis AX in the seconddirection SD, and also moves towards the feeder 14 in a directionsubstantially opposite the first direction, as illustrated in FIG. 8. Atthe same time, or about the same time, the first forming member 20 movessubstantially in the first direction FD as a small amount of formablematerial is provided in the first direction along the axis AX so as tomake room for the second forming member 30 in between the feeder 14 andthe first forming member 20.

FIGS. 9A-C illustrate the rotation of the second forming member 30 about90° from its orientation illustrated in FIGS. 1-4 and 6-8. In theillustrated embodiment, the second forming member 30 is rotated in acounterclockwise direction. In an embodiment, the second forming member30 may be rotated in a clockwise direction. Also, in an embodiment, thesecond forming member 30 may be rotated about 180°. The illustratedembodiment is not intended to be limiting in any way.

The second forming member 30 then moves in the third direction TDtowards the formable material 12, as illustrated in FIG. 10, engages theformable material 12 with the second engaging surface 35, and continuesto move in the third direction TD, as illustrated in FIG. 11. At thesame time, or about the same time, that the second engaging surface 35of the second forming member 30 moves across the axis AX and to theposition illustrated in FIG. 11, a suitable length of the formablematerial 12 is provided (i.e. drawn or fed) to accommodate for thedistance traveled by the second engaging surface 35 relative to the axisAX.

Similar to the movement of the first forming member 20 illustrated inFIG. 4, the first forming member 20 then disengages from the formablematerial 12 and moves away from the formable material in the thirddirection TD, as illustrated in FIG. 12. In addition, the first formingmember 20 moves towards the feeder 14 in a direction that issubstantially opposite the first direction FD. At the same time, orabout the same time, the second forming member 30 moves in the firstdirection FD as a small amount of formable material 12 is provided inthe first direction, desirably at about the same rate that the secondforming member 30 moves in the first direction FD, to make room for thefirst forming member 20 in between the feeder 14 and the second formingmember 30.

FIGS. 13A-C illustrate the rotation of the first forming member 20 about90° from its orientation illustrated in FIGS. 6-8 and 10-12 in thecounterclockwise direction. As noted above, in other embodiments, thefirst forming member 20 may be rotated in a clockwise direction and/ormay be rotated about 180°. The illustrated embodiment is not intended tobe limiting in any way.

The first forming member 20 then moves in the second direction SDtowards the formable material 12, as illustrated in FIG. 14, engages theformable material 12 with the third engaging surface 27, and continuesto move in the second direction SD, as illustrated in FIG. 15. At thesame time, or about the same time, that the third engaging surface 27 ofthe first forming member 20 moves across the axis AX and to the positionillustrated in FIG. 15, a suitable length of the formable material 12 isprovided to accommodate for the distance traveled by the third engagingsurface 27 relative to the axis AX.

Similar to the movement of the second forming member 30 that isrepresented in FIG. 7, the second forming member 30 then moves away fromthe formable material 12 and away from the axis AX in the seconddirection SD, and also moves towards the feeder 14 in a directionsubstantially opposite the first direction, as illustrated in FIG. 16.At the same time, or about the same time, the first forming member 20moves substantially in the first direction FD and a small amount offormable material is provided in the first direction along the axis AXso as to make room for the second forming member 30 in between thefeeder 14 and the first forming member 20.

FIGS. 17A-C illustrate the rotation of the second forming member 30 inthe counterclockwise direction about 90° from its orientationillustrated in FIGS. 10-12 and 14-16. As noted above, in otherembodiments, the second forming member 30 may be rotated in a clockwisedirection and/or may be rotated about 180°. The illustrated embodimentis not intended to be limiting in any way.

The second forming member 30 then moves in the third direction TDtowards the formable material 12, as illustrated in FIG. 18, engages theformable material 12 with the third engaging surface 37, and continuesto move in the third direction TD, as illustrated in FIG. 19. At thesame time, or about the same time, that the third engaging surface 37 ofthe first forming member 30 moves across the axis AX and to the positionillustrated in FIG. 19, the feeder 14 feeds a suitable length of theformable material 12 to accommodate for the distance traveled by thethird engaging surface 37 relative to the axis AX.

Similar to the movement of the first forming member 20 illustrated inFIG. 4, the first forming member 20 then disengages from the formablematerial 12 and moves away from the formable material in the thirddirection TD, as illustrated in FIG. 20. In addition, the first formingmember 20 moves towards the feeder 14 in a direction that issubstantially opposite the first direction FD. At the same time, orabout the same time, the second forming member 30 moves in the firstdirection FD as a small amount of formable material 12 is provided inthe first direction, desirably at about the same rate that the secondforming member 30 moves in the first direction FD, to make room for thefirst forming member 20 in between the feeder 14 and the second formingmember 30.

FIGS. 21A-C illustrate the rotation of the first forming member 20 about90° from its orientation illustrated in FIGS. 14-16 and 18-20 in thecounterclockwise direction. As noted above, in other embodiments, thefirst forming member 20 may be rotated in a clockwise direction and/ormay be rotated about 180°. The illustrated embodiment is not intended tobe limiting in any way.

The first forming member 20 then moves in the second direction SDtowards the formable material 12, as illustrated in FIG. 22, engages theformable material 12 with the fourth engaging surface 29, and continuesto move in the second direction SD, as illustrated in FIG. 23. At thesame time, or about the same time, that the fourth engaging surface 29of the first forming member 20 moves across the axis AX and to theposition illustrated in FIG. 23, a suitable length of the formablematerial 12 is provided to accommodate for the distance traveled by thefourth engaging surface 29 relative to the axis AX.

Similar to the movement of the second forming member 30 that isrepresented in FIG. 7, the second forming member 30 then moves away fromthe formable material 12 and away from the axis AX in the seconddirection SD, and also moves towards the feeder 14 in a directionsubstantially opposite the first direction, as illustrated in FIG. 24.At the same time, or about the same time, the first forming member 20moves substantially in the first direction FD and a small amount offormable material is provided in the first direction along the axis AXso as to make room for the second forming member 30 in between thefeeder 14 and the first forming member 20.

FIGS. 25A-C illustrate the rotation of the second forming member 30 inthe counterclockwise direction about 90° from its orientationillustrated in FIGS. 18-20 and 22-24. As noted above, in otherembodiments, the second forming member 30 may be rotated in a clockwisedirection and/or may be rotated about 180°. The illustrated embodimentis not intended to be limiting in any way.

The second forming member 30 then moves in the third direction TDtowards the formable material 12, as illustrated in FIG. 26, engages theformable material 12 with the fourth engaging surface 39, and continuesto move in the third direction TD, as illustrated in FIG. 27. At thesame time, or about the same time, that the fourth engaging surface 39of the first forming member 30 moves across the axis AX and to theposition illustrated in FIG. 27, the feeder 14 feeds a suitable lengthof the formable material 12 to accommodate for the distance traveled bythe fourth engaging surface 39 relative to the axis AX.

FIGS. 28-36 illustrate another embodiment of a method of forming a waveform in accordance with another embodiment of the present invention. Asillustrated in FIG. 28, the method starts with providing a length of theformable material 12 in between the first forming member 20 and thesecond forming member 30 in the first direction FD. FIG. 29 illustratesthe first forming member 20 being moved in the second direction SD sothat the first engaging surface 23 engages the formable material 12 anddeforms the formable material 12 while the second forming member 30remains stationary.

As illustrated in FIG. 30, the first forming member 20 and the secondforming member 30 are moved in the first direction so that a length L ofthe formable material may be drawn out of the feeder 14. The length Lshould be greater than or equal to the desired length of next strut ofthe wave form. As illustrated in FIG. 31, the first forming member 20and the second forming member 30 are moved in the third direction TD asthe first engaging surfaces 23, 33 engage the formable material 12. Thefirst forming member 20 and the second forming member 30 are also movedin a fourth direction QD that is opposite the first direction, asillustrated in FIG. 32. In an embodiment, rather than the first formingmember 20 and the second forming member 30 being moved in the seconddirection SD and the fourth direction QD sequentially, the first formingmember 20 and the second forming member 30 may be moved along an arc ortrajectory, as indicated by the dashed line TQD in FIG. 32.

After the portion of the wave form has been formed, as illustrated inFIG. 32, the first forming member 20 is moved in the fourth direction QDto a position that is in between the second forming member 30 and thefeeder 14, as illustrated in FIG. 33. In addition, the first formingmember 20 may be rotated, as illustrated in FIGS. 5A-C. With the firstforming member 20 in this position, the first forming member 20 and thesecond forming member 30 may be moved in the first direction FD so thatthe formable material 12 may be drawn in the first direction by a lengthL, as illustrated in FIG. 34. As before, the length L is greater than orequal to the desired length of the next strut of the wave form.

FIG. 35 illustrates the first forming member 20 engaging the formablematerial 12 with the second engaging surface 25 as the first formingmember 20 and the second forming member 30 are moved in the seconddirection SD. At the same time, or after the first forming member 20 andthe second forming member 30 have been moved in the second direction SD,the first forming member 20 and the second forming member 30 are movedin the fourth direction QD, as illustrated in FIG. 36. FIG. 36 alsoillustrates an arc or trajectory, represented by the line SQD that thefirst forming member 20 and the second forming member 30 may takeinstead of the sequential linear movements in the second direction SDand the fourth direction QD. The second forming member 30 may be movedin the fourth direction QD to a position in between the first formingmember 20 and the feeder 14, and the method depicted by FIGS. 30-36 maybe repeated until the desired wave form is formed.

The first forming member 20 and the second forming member 30 may bemoved away from the wave form being created at any time and rotated asillustrated in, for example, FIGS. 5A-C, 9A-C, 13A-C, 17A-C, 21A-C, and25A-C, so that crowns of different radii may be formed. As noted above,the first forming member 20 and the second forming member 30 may also berotated in a clockwise direction. The illustrated embodiments are notintended to be limiting in any way.

It has been found that the method of creating the wave form that isillustrated in FIGS. 30-36 forms struts that may be perfectly straight,or very close to being perfectly straight, and the struts may be formedwithout being drawn over one of the engaging surfaces. Drawing theformable material over one of the engaging surfaces may create struts inthe wave form that may be slightly curved.

The steps illustrated in the embodiment of FIGS. 2-27 may be mixed inwith the steps illustrated in the embodiment of FIGS. 28-36, asappropriate, in order to achieve the desired wave form.

After the apparatus has completed the methods illustrated by FIGS. 2-27and FIGS. 28-36, a wave form 100 having a plurality of waves includingcrowns, or curved portions, and substantially straight segments isformed, as illustrated in FIG. 37. As illustrated, the wave formincludes two crowns 62 that have a first radius, as defined by the firstengaging surfaces 23, 33, two crowns 64 that have a second radius, asdefined by the second engaging surfaces 25, 35, two crowns 66 that havea third radius, as defined by the third engaging surfaces 27, 37, andtwo crowns 68 that have a fourth radius, as defined by the fourthengaging surfaces 29, 39. By having forming members 20, 30 with engagingportions having engaging surfaces defined by different radii, the radiiof the crowns within the wave form 100 may be varied.

Although the wave form 100 illustrated in FIG. 37 includes two crownshaving the same radius next to each other along the wave form 100, theapparatus 10 may be controlled to provide any desired wave form 100 thatincludes crowns 62, 64, 66, 68 in any order. Also, although fourengaging surfaces are illustrated for each forming member, more or lessengaging surfaces may be provided. In addition, the lengths of thesubstantially straight segments may be varied by controlling themovement of the first and second forming members 20, 30 in directionsperpendicular to the axis AX and/or by providing engaging portions 22,24, 26, 28, 32, 34, 36, 38 having different lengths. For example, FIG.38 illustrates a wave form 200 that may be formed by the apparatus 10.As illustrated, crowns of different radii 62, 64, 66, 68 are more randomalong the wave form 200, and the lengths of the substantially straightsegments between the crowns are also more random, as compared to thewave form 100 illustrated in FIG. 37.

The controller 16 may be programmed with the desired wave form andcorresponding signals may be communicated to the feeder 14 and theactuators 40, 50 that move the first and second forming members 20, 30,so that the first and second forming members 20, 30 are moved relativeto the feeder 14 and the formable member 12 accordingly. The formingapparatus 10 uses multi-axis motions to deform the formable material 12and create a specific wave form or stent pattern that creates a stenthaving substantially perpendicular ends when wound about mandrel orother suitable structure. In an embodiment, the forming apparatus uses amulti-slide to create the multi-axis motions, but it is not necessary touse a multi-slide to create such motions. Other arrangements arecontemplated to be within the scope of the invention. In addition, thecontroller 16 may send corresponding signals to the motors or actuatorsthat provide rotational movement to the first and second forming membersto change the radii of the crowns and/or the length of the substantiallystraight segments.

The formable material 12 may be a wire or strip material thatplastically deforms when deformed by the first and second formingmembers 20, 30 so that the wave form generally holds its shape afterbeing formed. By adjusting the shape and size of the first and secondforming members 20, 30, the relative motions of the first and secondforming members 20, 30 in relation to each other, the formable material12, and the feed rate or draw rate and/or movement of the feeder 14,various amplitudes, periods, and shapes may be created within the waveform to form the overall desired shape for the stent.

Embodiments of the stents made using the method and apparatus discussedabove may be formed from a wire or a strip of suitable material. Incertain embodiments, the stents may be formed, i.e., etched or cut, froma thin tube of suitable material, or from a thin plate of suitablematerial and rolled into a tube. Suitable materials for the stentinclude but are not limited to stainless steel, iridium, platinum, gold,tungsten, tantalum, palladium, silver, niobium, zirconium, aluminum,copper, indium, ruthenium, molybdenum, niobium, tin, cobalt, nickel,zinc, iron, gallium, manganese, chromium, titanium, aluminum, vanadium,carbon, and magnesium, as well as combinations, alloys, and/orlaminations thereof. For example, the stent may be formed from a cobaltalloy, such as L605 or MP35N®, Nitinol (nickel-titanium shape memoryalloy), ABI (palladium-silver alloy), Elgiloy® (cobalt-chromium-nickelalloy), etc. It is also contemplated that the stent may be formed fromtwo or more materials that are laminated together, such as tantalum thatis laminated with MP35N®. The stents may also be formed from wireshaving concentric layers of different metals, alloys, or othermaterials. Embodiments of the stent may also be formed from hollowtubes, or tubes that have been filled with other materials. Theaforementioned materials and laminations are intended to be examples andare not intended to be limiting in any way.

While at least one exemplary embodiment has been presented in theforegoing detailed description of the invention, it should beappreciated that a vast number of variations exist. It should also beappreciated that the exemplary embodiment or exemplary embodiments areonly examples, and are not intended to limit the scope, applicability,or configuration of the invention in any way. Rather, the foregoingdetailed description will provide those skilled in the art with aconvenient roadmap for implementing an exemplary embodiment of theinvention, it being understood that various changes may be made in thefunction and arrangement of members described in an exemplary embodimentwithout departing from the scope of the invention as set forth in theappended claims.

What is claimed is:
 1. A method for forming a wave form for a stent, themethod comprising: providing a length of a formable material from asupply of the formable material in a feeder along an axis in a firstdirection in between a first forming member and a second forming member,the second forming member being positioned closer to the feeder than thefirst forming member; moving a first forming portion of the firstforming member into contact with the formable material and across theaxis in a second direction substantially perpendicular to the firstdirection; and folding the formable material over a first formingportion of the second forming member by moving the second forming memberand the first forming member in a third direction substantially oppositethe second direction and moving the second forming member and the firstforming member in a fourth direction substantially opposite the firstdirection; disengaging the first forming member from the formablematerial; rotating the first forming member, until a second formingportion of the first forming member extends in the second direction,wherein the first and second forming portions are different sizes;moving the second forming portion of the first forming member intoengagement with the formable material at a position closer to the feederthan the second forming member; drawing a length of the formable memberfrom the feeder with the first forming member and the second formingmember; and folding the formable material over the second formingportion of the first member by moving the first forming member and thesecond forming member in the second direction and moving the firstforming member and the second forming member in the fourth direction. 2.The method according to claim 1, wherein the first forming portion ofthe first forming member has a distal end having a first radius and thesecond forming portion of the first forming member has a distal endhaving a second radius that is different from the first radius.
 3. Themethod according to claim 1, further comprising: disengaging the secondforming member from the forming material; rotating the second formingmember; moving a second forming portion of the second forming memberinto engagement with the formable material at a position closer to thefeeder than the first forming member; drawing a length of the formablemember from the feeder with the first forming member and the secondforming member; and folding the formable material over the secondforming portion of the second forming member by moving the secondforming member and the first forming member in the third direction andmoving the second forming member and the first forming member in thefourth direction.
 4. The method according to claim 1, wherein the secondforming member and the first forming member are moved in the thirddirection and then are moved in the fourth direction sequentially. 5.The method according to claim 1, wherein the second forming member andthe first forming member are moved in the third direction and in thefourth direction simultaneously.
 6. The method according to claim 1,wherein engaging surfaces of the first and second forming portions aredifferent sizes.
 7. The method according to claim 6, wherein theengaging surfaces of the first and second forming portions are definedby different radii.
 8. A method for forming a wave form for a stent, themethod comprising: providing a length of a formable material from asupply of the formable material in a feeder along an axis in a firstdirection in between a first forming member and a second forming member,the first forming member configured to be movable along two orthogonalaxes, the second forming member being positioned closer to the feederthan the first forming member; moving a first forming portion of thefirst forming member into contact with the formable material and acrossthe axis in a second direction substantially perpendicular to the firstdirection; and folding the formable material over a first formingportion of the second forming member by moving the second forming memberand the first forming member in a third direction substantially oppositethe second direction and moving the second forming member and the firstforming member in a fourth direction substantially opposite the firstdirection; disengaging the first forming member from the formablematerial; rotating the first forming member in a plane defined by thetwo orthogonal axes; moving a second forming portion of the firstforming member into engagement with the formable material at a positioncloser to the feeder than the second forming member; drawing a length ofthe formable member from the feeder with the first forming member andthe second forming member; and folding the formable material over thesecond forming portion of the first member by moving the first formingmember and the second forming member in the second direction and movingthe first forming member and the second forming member in the fourthdirection.
 9. The method according to claim 8, wherein the first formingportion of the first forming member has a distal end having a firstradius and the second forming portion of the first forming member has adistal end having a second radius that is different from the firstradius.
 10. The method according to claim 8, further comprising:disengaging the second forming member from the forming material;rotating the second forming member; moving a second forming portion ofthe second forming member into engagement with the formable material ata position closer to the feeder than the first forming member; drawing alength of the formable member from the feeder with the first formingmember and the second forming member; and folding the formable materialover the second forming portion of the second forming member by movingthe second forming member and the first forming member in the thirddirection and moving the second forming member and the first formingmember in the fourth direction.
 11. The method according to claim 8,wherein the second forming member and the first forming member are movedin the third direction and then are moved in the fourth directionsequentially.
 12. The method according to claim 8, wherein the secondforming member and the first forming member are moved in the thirddirection and in the fourth direction simultaneously.